Q: Which build do I need?

Q: How can I access the box?

Q: What is the SSH login?

user: root
password: libreelec

Q: How do I change the SSH password?

It is not possible to change the password (without recompiling the distro with a different one) because the password file is contained inside the read-only squashfs SYSTEM file (the read-only part is the challenge). Instead of changing the password there are two main options: a) You can enable/disable SSH easily within the Kodi GUI, so only enable it when really needed (by default it is disabled) and then disable it again when done, or b) Create and push an SSH public key to the box, then disable SSH password authentication in the settings add-on. If you're going to use SSH regularly the second option is best as SSH keys offer much better protection than passwords.

Q: What is the difference between LibreELEC and Kodi?

LibreELEC is a small Linux-distro. Kodi is a media center software running on that distro.

Q: How am I able to help?

In any way you want. You are able to contribute code, make donations, give support at forums/IRC or make documentations at our Wiki.